7‐Hydroxycoumarin as a Novel Film‐Forming Additive for LiNi0.5Mn1.5O4 Cathode at Elevated Temperature. Issue 22 (20th November 2020)

• Record Type: Journal Article
• Authors: Shang, Huimin; Jiang, Jinjin; Zhang, Huan; Niu, Wenchao; Qiao, Yingjun; Zhou, Hanxiao; Li, Tianhui; Qu, Meizhen; Peng, Gongchang; Xie, Zhengwei
• Is Part Of: ChemElectroChem. Volume 7:Issue 22(2020)
• Page Start: 4655
• Page End: 4662
• Publication Date: 2020-11-20
• Subjects: LiNi0.5Mn1.5O4 -- 7-hydroxycoumarin -- additive -- cyclic stability -- elevated temperature; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.202001167
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: A novel additive, 7‐hydroxycoumarin (7‐HC), is employed to construct a stable interface film on the LiNi0.5 Mn1.5 O4 cathode to improve the cyclic stability of Li/LiNi0.5 Mn1.5 O4 cells at elevated temperature (ca. 55 °C). In the 0.01 wt% 7‐hydroxycoumarin‐containing electrolyte, the capacity retention of Li/LiNi0.5 Mn1.5 O4 cell increases from 78.15 % to 95.64 % at elevated temperature after 100 cycles at 1 C rate. Through theoretical calculations and ex‐situ analysis, it suggests that 7‐HC is susceptible to oxidation than other components of the electrolyte to form a thin and stable film on the surface of LiNi0.5 Mn1.5 O4 cathode. The thin and stable film can effectively reduce the interface oxidation reaction and the "cross‐talk" between the positive electrode and negative electrode and effectively inhibit the structural changes of LiNi0.5 Mn1.5 O4 caused by dissolved transition metals in subsequent cycles, thereby improving the cyclic stability of the cell at elevated temperature. Abstract : Thin but strong : The thin and robust film containing 7‐HC effectively separates the LiNi0.5 Mn1.5 O4 from the electrolyte, reduces the side reactions between LiNi0.5 Mn1.5 O4 and electrolyte and reduces the corrosion of HF on the surface of LiNi0.5 Mn1.5 O4, improving the cyclic stability of the Li/LiMn0.5 Ni1.5 O4 cells at elevated temperature.